1. Field of the Invention
This invention relates to a thermoresponsive polymer, which can change and regulate its polarity and hydrogen bonding performance by changing temperature, and a production method thereof.
2. Background Art
In a compound in which its structure is changed by temperature, pH, light or the like stimulus, its hydrophilic property, hydrophobic property and the like polarities are changed accompanied by its structural changes. A thermoresponsive polymer is known as a compound which causes a structural change by temperature. Illustratively, poly(N-acryloylglycineamide) can be exemplified. This polymer is characterized in that the polymer is dissolved in an aqueous solution when its temperature becomes 38 to 39° C. or more, and the polymer is in-solubilized at 35 to 36° C. or less. This means that it has an upper critical solution temperature (e.g., see Non-patent Reference 1).
[Non-patent Reference 1] Howard C. H. and Norman W. S., Polymer Letters, vol. 2 (1964)
However, a polymer having a critical solution temperature has a problem in that the critical solution temperature is apt to change greatly caused by the interfusion of a salt or increase of pH, and the critical solution temperature therefore becomes difficult to be expressed.
In view of the aforementioned present situation, there is a demand for a material which, for example, expresses its critical solution temperature making use of hydrogen bond even in an aqueous solution containing a buffer or salt, and stably shows small variation width of the critical solution temperature, interacts with a substance such as a component in the living body and can therefore be used efficiently in the isolation of the substance of interest.